The application is based on Japanese patent application 2000-320761 number (application on October 20th, 2000), and its content is put down in writing in this application as the document of quoting.
The best mode that carries out an invention
Below, the situation that the present invention is used for the wheel type hydraulic excavator is described with Fig. 1~Figure 12.The wheel type hydraulic excavator is provided with wheeled runner, the solid of rotation that can be connected with runner pivotally and is installed in operation fixture on the solid of rotation.
Fig. 1 is the hydraulic circuit diagram of expression wheel type hydraulic excavator of the present invention.This oil hydraulic circuit is provided with: by there not being illustrated engine-driven main pump 10,20; 4 control valves 11~14 that set side by side with main pump 10; 5 control valves 21~25 that set side by side with main pump 20.But also be provided with: the rotary motor 35 that uses driving motors 1 that the pressure oil by control valve 11,25 controls drives, uses bucket cylinder 32 that the pressure oil by control valve 12 controls drives, uses boom cylinder 33 that the pressure oil by control valve 13,23 controls drives, uses the support arm oil cylinder 34 that the pressure oil by control valve 14,22 controls drives and use the pressure oil by control valve 21 controls to drive.Control valve 24 is standby control valves.
Driving motors 1, boom cylinder 33, support arm oil cylinder 34 are by the interflow drive circuit, and this loop, interflow is movement speed to be increased the pressure oil interflow of main pump 10,20 outputs.Master control pump 10A supplies with master control to following main control loop and presses oil, and supplies with pressure oil to following detection loop (Fig. 5), and this detection loop is to be used to detect the operation/inoperation of accelerator pedal, the operation of operating stem/inactive.
Fig. 2 is the schematic representation of the expression oil hydraulic circuit details of travelling shown in Figure 1.What the oil hydraulic circuit that travels of Fig. 2 was represented is that main pump 10 shown in Figure 1 uses control valve 11 that part of with travelling.As shown in Figure 2, the pressure oil of variable capacity type main pump 10 outputs that driven by motor (prime mover) 2 is being adorned the brake valve 4 of back pressure valve 3 and is being supplied with variable capacity type driving motors 1 through inner by control valve 11 control its direction and flow.The revolution of driving motors 1 is by transmission device 5 speed changes.Pass to tire 8 through the revolution of the driving motors 1 of speed change by live axle 6, axletree 7, the wheel type hydraulic excavator is travelled.On the pipeline between main pump 10 and the control valve 11, pressure transducer 41 is being set.The travel pump pressure of main pump 10 of driving pressure (motor driven pressure) of 41 pairs of conducts of pressure transducer detects.The speed ratio of transmission device 5 be in low-speed region still high-speed region be do not have in by figure expression operating stem operation and determine.
The amount of deflection of main pump 10 is adjusted by pump governor 10B.Pump governor 10B is provided with torque limit portion.Pump discharge head is fed back to this torque limit portion, carries out horsepower control.The relation (P-qp plotted curve) of having represented the pump pressure P and the pump amount of deflection qp of main pump 10 among Fig. 3.Horsepower control is what to carry out according to P-qp plotted curve shown in Figure 3.By the pump amount of deflection qp of regulator 10B control main pump 10, make can not surpass motor output by the head pressure P of pump and the load of pump amount of deflection qp decision.Promptly, in the time will implementing feedback pressure and import regulator 10B, be along P-qp plotted curve shown in Figure 3 and the control pump amount of deflection.
Maximum speed in the time of will travelling respectively in embodiments of the present invention, as described below, is controlled to that 1600rpm, the rotating speed when high pass filter is travelled are controlled to 2150rpm, the maximum speed during with operation is controlled to 1950rpm.
The amount of deflection of driving motors 1 is adjusted by regulator 1A.Regulator 1A makes the effect that can form with the corresponding master control pressure of motor driven pressure.Thus, motor amount of deflection qm can convert for example two stages of size to.Promptly, when motor driven pressure is specified value P1 when above, the above master control pressure effect of specified value is just arranged on the regulator 1A, qm sets maximum for the motor amount of deflection.And when motor driven pressure was discontented with specified value P1, qm set minimum for the motor amount of deflection.
Main control loop is provided with master control pump 10A, with entering into of accelerator pedal 15 a pair of main control valve 16A, the 16B of travelling of 2 master control pressure takes place correspondingly.Also be provided with a pair of one-way throttle valve 17A, the 17B that link to each other with main control valve 16A, 16B, make the pressure oil delay that revert to main control valve 16A, 16B.
Accelerator pedal 15 be by its front side enter into operation (preceding stepping on) and rear side enter into operation (post legged), can distinguish forwards and rotate with the rear.Drive main control valve 16B by stepping on before the accelerator pedal 15.Thus the master control pressure of main control loop output is acted on the guide openings of control valve 11.Control valve 11 and master control pressure correspondingly are transformed into F position or R position.Its result acts on the driving motors 1 the pressure oil of main pump 10 output, with one with the corresponding speed of amount of pedal operation, motor 1 is turned round, make vehicle driving.In the present embodiment, correspondingly make engine speed change with the operation amount of accelerator pedal 15, be not so-called acceleration control, be correspondingly the aperture of control valve 11 is controlled with the operation amount of accelerator pedal 15, adjust the speed of a motor vehicle by so-called valve control.The valve control mode does not need to be used to detect the sensor of the master control pressure of accelerator pedal 15 outputs.
Step in the vehicle driving that forms before by accelerator pedal 15, in case stop pedal operation, the main control valve 16A that then travels just cuts off the pressure oil of master control pump 10A output, and its exit orifice is communicated with the groove cylinder.Act on pressure oil on the guide openings of control valve 11, by one-way throttle valve 17A, travel main control valve 16A and revert in the groove cylinder.At this moment, the throttling that is subjected to one-way throttle valve 17A owing to the pressure oil that returns is dwindled, and makes control valve 11 convert the neutral position gradually to.When control valve 11 converted the neutral position to, the pressure oil of exporting from main pump 10 just revert to the groove cylinder.Cut-out converts back pressure valve 3 to neutral position shown in Figure 3 to the supply of the drive pressure oil of driving motors 1.
Under this occasion, vehicle is continued by the effect of inertial force to travel.Driving motors 1 becomes pumping action from the motor effect, becomes B aperture side suction among the figure, the discharge of A aperture side.Dwindle by the throttling (neutral throttling) of the neutral position of back pressure valve 3 from the pressure oil of driving motors 1 output.The pressure of the pressure oil between back pressure valve 3 and the driving motors 1 is risen, act on the driving motors 1 as retardation pressure.Its result makes driving motors 1 that retarding torque take place, and makes car brakeing.When sucking low on fuel in the pumping action, oil mass is replenished to driving motors 1 by main pump 18.The maximum pressure of retardation pressure is limited by relief valve 19A, 19B.
The operation of wheel type hydraulic excavator is attached to be adorned by for example suspension rod, support arm, scraper bowl etc. constitute.Support arm master control operating stem, suspension rod master control operating stem and scraper bowl master control operating stem are being set respectively in the operation office for train receiving departure of wheel type hydraulic excavator.Fig. 4 represents the suspension rod main control loop, represents operation fixture main control loop with this.When operation suspension rod operating stem BL, with the operation amount of suspension rod operating stem BL correspondingly, reduce pressure by the pressure oil of reduction valve (main control valve PV) with master control pump 10A output.With through the pressure of the master control pump 10A output of main control valve PV decompression correspondingly, the suspension rod of hydraulic pressure master control reversable is changed with control valve 13,23 (Fig. 1).Thus with the pressure oil of main pump 10 output, import boom cylinder 33 by control valve 13,23, make the action of suspension rod rough ground by boom cylinder 33 flexible.When suspension rod operating stem BL being operated when making suspension rod rising side, with the bottom side of Pressure oil feeder boom cylinder 33.When suspension rod operating stem BL being operated when making suspension rod reduce side, with the bar side of Pressure oil feeder boom cylinder 33.
The present invention is that the serviceability to the operating stem of the serviceability of accelerator pedal 15 and above-mentioned operation fixture detects, and correspondingly controls engine speed with each serviceability.Above-mentioned accelerator pedal 15 is the revolutions that are used for regulating the driving motors 1 that makes vehicle driving.Below, the detecting method of the serviceability of the serviceability of accelerator pedal 15 and operating stem is described.
Fig. 5 is that explanation is the loop schematic representation of the operation/inoperation state of operation/inoperation state of being used to detect accelerator pedal 15, operating stem.From the pressure oil of master control pump 10A output by pipeline L1, by scraper bowl with control valve 12, suspension rod with control valve 13, support arm with control valve 14, revolution with control valve 21, support arm with control valve 22, suspension rod with control valve 23 and standby control valve 24 and the lead-in groove cylinder.And, from the pressure oil of master control pump 10A output by pipeline L2, by driving motors with control valve 11 and 25 and the lead-in groove cylinder.
Throttle valve 42,43 is being set respectively on pipeline L1, the L2.Operation is being set with pressure switch 44 with travel respectively with pressure switch 45 on pipeline L1, the L2 in the downstream side of throttle valve 42,43.When in the control valve 12~14,21~24 any one operated, pipeline L1 is cut off, the pressure of the downstream side pipeline L1 of throttle valve 42 is risen.Thus, operation is connected with pressure switch 44, control valve 12~14,21~24 is detected, promptly, the operation of operating stem is detected.Equally,, pipeline L2 is cut off, the pressure of the downstream side pipeline L2 of throttle valve 45 is risen operation control valve 11,25 o'clock.Thus, will travel and connect, control valve 11,25 will be detected, promptly, the operation of accelerator pedal 15 is detected with pressure switch 45.
Below, control loop is described, this control loop is used to control engine speed, and it is correspondingly to control with the serviceability of the accelerator pedal 15 that detected and the serviceability of operating stem above-mentionedly.Fig. 6 is the control loop skeleton diagram that is used to control engine speed.It is with the controller 50 that devices such as CPU constitute each machine to be controlled.
The regulator 26 of motor 2 is connected with pulse motors 28 by link mechanism 27, by the revolution of pulse motors 28 engine speed is controlled.Promptly, by the just commentaries on classics of pulse motors 28, engine speed is risen; By it counter-rotating, engine speed is reduced.The revolution of this pulse motors 28 is controlled by the control signal of controller 50.Potentiometer 29 is connected with regulator 26 by link mechanism 27.Potentiometer 29 detects the suitable governor lever angle of rotating speed with motor 2.Detected governor lever angle is input to controller 50 as engine control rotational speed N θ.
Also connecting the speed setting dial 46 that is used for setting engine speed on the controller 50 respectively according to the operation of operation office for train receiving departure output, the idle running switch 70 of instruction is assigned in control to racing speed, pressure transducer 41 shown in Figure 1, operation shown in Figure 5 pressure switch 44, travel with pressure switch 45, the speed setting device 47 of maximum speed 1600rpm when setting above-mentioned travelling, the speed setting device 48 of rotating speed 2150rpm when setting above-mentioned high pass filter and travelling, set the speed setting device 49 of the minimum speed (for example 900rpm) of regulation, set the speed setting device 71 of the racing speed (for example 1050rpm) of regulation.With speed setting dial 46 with speed setting in the scope of 900rpm~1950rpm.And with operation with racing speed with travel and set equal numerical value (1050rpm) for racing speed.
Fig. 7 is the schematic representation of the engine speed control processing details in the explanation controller 50.Corresponding rotating speed of target (dial rotating speed) Na of signal V that function generator 51 is exported according to the such characteristic of predetermined diagram, output and speed setting dial (potentiometer) 46.Rotating speed of target Na input minimum value is selected loop 53.When rotating speed limit switch 52 closures, the regulation rotating speed 1600rpm input minimum value that speed setting device 47 is set is selected loop 53.Select loop 63 pairs of settings rotating speed 1600rpm and dial rotational speed N a to compare by minimum value, select the maximum value of two inputs.Rotating speed limit switch 52 is closure by closure signal effect as described below.
From travelling with the on/off signal difference regulator 54 input time and the fault verification loop 55 of pressure switch 45 outputs.Time regulator 54 t0 (for example 2 seconds) at the appointed time carries out timing to the signal of exporting with pressure switch 45 that travels, and the signal of stipulating is outputed to closure signal follower 56.The corresponding closure signal of signal of 56 outputs of closure signal follower and time regulator 54 outputs makes rotating speed limit switch 52 closures through closure signal switch 57.After 54 couples of stipulated time t0 of time regulator carried out timing, closure signal follower 56 continued the output closure signal, up to input and the irrelevant reset signal of the state of time regulator 54.Time regulator 54 resets with the shutoff signal of pressure switch 45 output or by the timing of the stipulated time t0 of connection signal by travelling.
Connection/shutoff signal of exporting with pressure switch 44 from operation is input to closure signal follower 56 and closure signal switch 57 respectively.During from the 44 input connections (reset signal) of operation usefulness pressure switch, closure signal follower 56 stops the output of closure signal.Closure signal switch 57 is opened with the connection signal effect of pressure switch 44 outputs by operation; The closure by the shutoff signal effect.
Travel and judge with the fault of pressure switch 45 in 55 pairs in fault verification loop.Travel and just often be adjusted to input, can exporting 0.5V (shutoff signal) or 4.5V (connection signal 55) with respect to 5V with pressure switch 45.When travelling with pressure switch 45 output abnormality signals, fault verification loop 55 outputs to rotating speed limit switch 52 with closure signal.When travelling with pressure switch 45 output 5V, fault verification loop 55 is judged to be switch 45 broken strings; During output 0V, be judged to be switch 45 short circuits.Thus, travelling when breaking down, with rotating speed limit switch 52 closures with pressure switch 45.
Connecting the pressure transducer 41 that is used to detect motor driven pressure on the function generator 58.At the testing signal Pd of pressure transducer 41 are specified values (such as switching to pressure P1 of motor amount of deflection qm) when above, function generator 58 output high level signals; Be when being discontented with specified value, the output low level signal.
Connecting on the AND gate circuit 59 and travelling with pressure switch 45 and function generator 58.Travelling with pressure switch 45 connect, promptly from travelling with pressure switch 45 input 4.5V, and during from function generator 58 output high level signals, AND gate circuit 59 outputs to switching signal and sets throw over switch 61.The switching signal of setting throw over switch 61 and AND gate circuit 59 outputs correspondingly, be transformed into contact a from contact b.Each contact a, the b that set throw over switch 61 are connected with speed setting device 48,49 respectively.When setting throw over switch 61 and be transformed into contact a, the setting rotating speed 2150rpm of speed setting device 48 is input to maximum value selects loop 62.When setting throw over switch 61 and be transformed into contact b, the setting rotating speed 900rpm of speed setting device 49 is input to maximum value selects loop 62.
Select loop 62 to select loop 53 selected rotating speeds to compare minimum value by maximum value, select maximum value wherein with setting rotating speed 2150rpm or 900rpm.
The on/off signal of idle running switch 70 outputs, operation are input to conversion loop 63 respectively with the on/off signal of pressure switch 44 outputs, the on/off signal of exporting with pressure switch 45 that travels.Carry out following processing in conversion loop 63, will open and close signal and output to delay switch 64, and switching signal is outputed to idle running throw over switch 66.The contact a of idle running throw over switch 66 is connected with delay control device 65, contact b is connected with maximum value selection loop 62, contact c is connected with the speed setting device 71 of setting racing speed.
When postponing switch 64 connections, postpone the delay control that control device 65 is stipulated; When disconnecting, make to postpone to control to reset.So-called to postpone control be such control, promptly, it drops to engine speed the racing speed of regulation at leisure.
Fig. 8 (a) and (b) are represented by the variation that postpones to control the engine speed that forms.The transverse axis express time t of Fig. 8 (a) and (b), the longitudinal axis is represented engine speed.Shown in Fig. 8 (a), when postponing switch 64 connections, (slope of straight line) makes the control rotating speed 1050rpm that engine speed (such as 1950rpm, 1600rpm) descends in certain proportion.Shown in Fig. 8 (b), the time that makes engine speed drop to racing speed can be and the irrelevant certain value of engine speed.Above delay control is as described below, postpones to control when will speed up pedal 15 disengagings in that operating stem is not operated; Do not postpone control when operating stem being broken away from that accelerator pedal 15 is not operated.
Fig. 9 is the flow chart that is used for illustrating the processing in above-mentioned conversion loop 63.Below, illustrate in the signal conversion processes of changing on the loop 63 with flow process shown in Figure 9.
At step S1, whether the signal determining vehicle of exporting with pressure switch 45 is in travelling state according to travelling.When travelling with pressure switch 45 output connection signals, when being judged to be travelling state, entering step S2, set sign 1.Then, at step S3, opening signal is outputed to delay switch 64.At step S4, making does not have the event counter of expression to reset on the figure.At step S5, output makes idle running throw over switch 66 be transformed into the signal of contact b, returns.
On the other hand, when travelling with pressure switch 45 output shutoff signals, step S1 is negated and is entered step S6.Step S6, according to operation with the signal of pressure switch 44 output, judge whether be in job state.When operation with pressure switch 44 output connection signals, when being judged to be this job state, enter step S7, set sign 0 and enter step S3.
When operation is exported shutoff signals, when step S6 is negated, entered step S8 with pressure switch 44.Whether connect at step S8, judgement idle running switch 70.Certainly be judged to be idle running switch 70 when connecting when step S8 makes, enter step S9; When making when negate judging, entering step S4.At step S9, the conversion timer is set.In case the conversion timer is set, just is performed until the timing that resets at step S4.
Then, at the numerical value of step S10, determination flag.When the numerical value of sign when being 0, promptly, currently be when being in job state, enter step S11.Whether stipulated time T1 (for example 3.5 seconds) has been carried out timing at step S11, judgement conversion timer.When step S11 is judged to be the conversion timer stipulated time T1 is done timing, then entered step S12.Export the signal that the throw over switch 66 that will dally is transformed into contact c at step S12, return.On the other hand, at the discontented stipulated time T1 of timing time that step S11 is judged to be the conversion timer, then enter step S5.
Numerical value at step S10, sign is 1 o'clock, promptly, current be when being in travelling state, enter step S13.At step S13, judge whether the conversion timer has carried out timing to stipulated time T2 (for example 5 seconds).When step S13 is judged to be the conversion timer stipulated time T2 is done timing, then entered step S14.Output at step S14, with shutdown signal and to postpone switch 64.Then, be transformed into the signal of contact a, return at step S15, the output throw over switch 66 that will dally.On the other hand, the discontented stipulated time T2 of timing time in that step S13 is judged to be the conversion timer then enters step S5.
As top such with the flowchart text of Fig. 9, in conversion loop 63, based on idle running switch 70, operation with pressure switch 44, travel with the signal of pressure switch 45, postpone switch 64 and the conversion and control of the throw over switch 66 that dallies.When according to the processing of being carried out with conversion loop 63 shown in Figure 9, when the throw over switch 66 that will dally is transformed into contact a, the rotating speed that postpones control device 65 outputs is input to servocontrol portion 67 as rotary speed instruction value Nin.When the throw over switch 66 that will dally is transformed into contact b, the rotating speed of selecting loop 62 to select by maximum value is input to servocontrol portion 67 as rotary speed instruction value Nin.When the throw over switch 66 that will dally was transformed into contact c, the rotating speed that the speed setting device 71 that is used to set racing speed is set was input to servocontrol portion 67 as rotary speed instruction value Nin.
Servocontrol portion 67 is the suitable control rotational speed N θ of the displacement amounts with governor lever 27 that detected by potentiometer 29, compare with the rotary speed instruction value Nin of input.Then, servocontrol portion 67 control impuls motors 28, make rotary speed instruction value Nin consistent with control rotational speed N θ.Figure 10 represents the program that servocontrol portion 67 paired pulses motors 28 are controlled.
At step S21, read in rotary speed instruction value Nin and control rotational speed N θ respectively.In step 22, deduct rotary speed instruction value Nin (N θ-Nin) from control rotational speed N θ.The result is included in the storage that does not have expression among the figure as the difference A of rotating speed.At step S23, with predetermined reference rotation speed difference K, whether judge | A| 〉=K.When step S23 is judged to be | during A| 〉=K, enter step S24.At step S24, whether judge speed discrepancy A>0.
When step S24 is judged to be when being A>0, be meant that control rotational speed N θ specific speed command value Nin is big.Enter step S25 thus, descend in order to make engine speed, the signal that instruction motor is reversed outputs to pulse motors 28.Make pulse motors 28 counter-rotatings thus, the rotating speed of motor 2 is descended.
On the other hand, when step S24 is judged to be when being A≤0, be meant that control rotational speed N θ specific speed command value Nin is little.Enter step S26 thus, improve in order to make engine speed, the signal that instruction motor is just being changeed outputs to pulse motors 28.Pulse motors 28 is just being changeed, the rotating speed of motor 2 is improved.
When step S23 makes negative judgement, enter step S27, the motor stop signal is outputed to pulse motors 28.Rotating speed with motor 2 is held in certain value thus.After carrying out step S25~step S27, the initial state of recurrence.
Below, the structure of hydraulic traveling vehicle of the present invention is described.Figure 11~Figure 14 is the time plot of expression engine speed and correlations such as pressure switch, pressure transducer.Below, the action of the moving vehicle under the various conditions is described with the time plot of Figure 11~Figure 14.
Figure 11, Figure 12 are the time plots that idle running switch 70 disconnects under the occasion.Under this occasion, engine speed is controlled between the maximum speed 2150rpm and minimum speed 900rpm of high pass filter when travelling.Figure 13, Figure 14 are the time plots under the idle running switch connection occasion.
(1) idle running switch 70 cuts off testing signal Pd<P1, dial rotational speed N a=1950rpm
Figure 11 (a)~(c) represents that under these conditions operation is with pressure switch 44, the time plot that travels and concern each other with pressure switch 45 and engine speed.
When the testing signal Pd of pressure transducer 41<P1, function generator 58 output low levels will be set throw over switch 61 and be transformed into contact b.And the setting rotating speed 900rpm of speed setting device 49 is input to maximum value sets 62 li in loop.The dial rotational speed N a=1950rpm of speed setting dial 46 is input to minimum value selection loop 53.When idle running switch 70 cut off, by the processing by above-mentioned conversion loop 63, the switch 66 that will dally often was transformed into contact b and goes up (the step S5 of Fig. 9).
When operating stem not being operated and accelerator pedal 15 is not operated, operation with pressure switch 44, travel and all export shutoff signal with pressure switch 45.Thus rotating speed limit switch 52 is opened, set loop 53 and maximum value setting loop 62 selection racing speed=1950rpm with minimum value.Selecteed dial rotational speed N a is input to servocontrol portion 67 as rotary speed instruction value Nin.By servocontrol portion 67 control impuls motors 28, make rotary speed instruction value Nin=1950rpm with consistent from the suitable racing speed Nin of the checkout value of potentiometer 29 outputs.Thus engine speed is controlled to dial rotational speed N a=1950rpm.
From above-mentioned state, accelerator pedal 15 ground of entering into are operated, and make vehicle begin to travel.Travel with pressure switch 45 output connection signals, make timer 54 actions.In the time of after timer 54 startings, through stipulated time t0 (=2), closure signal follower 56 output closure signal.Closure signal switch 57 cuts out with the shutoff signal of pressure switch 44 outputs by operation.For this reason, by the closure signal of closure signal follower 56 outputs rotating speed limit switch 52 is closed.The setting rotating speed 1600rpm input minimum value of speed setting device 47 is set loop 53.Set loop 53, maximum value selection loop 62 selection setting rotating speed 1600rpm by minimum value.Because idle running throw over switch 66 is in contact b, engine speed is controlled to setting rotating speed 1600rpm by servocontrol portion 67.Its result limits pump delivery, can prevent the excessive revolution (t1 among Figure 11 (a)) of driving motors 1.
After this, when the operation that stops accelerator pedal 15, make timer 54 reset (t2).But closure signal follower 56 continues the output closure signal, engine speed is remained on set rotating speed 1600rpm.Thus, Gu even reasons such as signal maintenance stop the operation to accelerator pedal 15, engine speed remains and is suppressed, and can prevent the increase of the expense of firing.
From this state (t2), when operating stem is operated, operation is with pressure switch 44 output shutoff signals, closure signal follower 56 resetted and stop the output of closure signal, and, open closed signaling switch 57 (t3).The result opens rotating speed limit switch 52, selects loop 53 selection dial rotational speed N a=1950rpm by minimum value.Engine speed is controlled to control rotational speed N a=1950rpm for this reason.Thus, engine speed is controlled to control rotational speed N a=1950rpm at once, makes the operation raising by the operation of operating stem.
After this, when the operation that stops operating stem, operation makes closure signal switch 57 close (t4) with pressure switch 44 output shutoff signals.At this moment, travel and do not export connection signal with pressure switch 45, closure signal follower 56 is not exported closure signal.At this moment limit switch 52 is being opened, and engine speed remains dial rotational speed N a=1950rpm.Thus,, still engine speed is held in dial rotational speed N a=1950rpm, can prevents the frequent change of rotating speed even operating stem is being carried out under the occasion of repeatable operation.
Shown in Figure 11 (b), when vehicle driving, be that engine speed is controlled to the state (t5) of setting rotating speed 1600rpm, when operating stem was operated, the connection signal of being exported with pressure switch 44 by operation made closure signal switch 57 open (t6).Thus, rotating speed limit switch 52 is opened, engine speed is controlled to dial rotational speed N a=1950rpm.
When vehicle driving, operating stem is operated, making engine speed is dial rotational speed N a=1950rpm (t7), stops the operation to operating stem after this, under steam.Owing to stop operation to operating stem, thereby operation becomes dissengaged positions with pressure switch 44, to travel with the shutoff signal of pressure switch 45 carry out the timer 54 of timing, through the timing of stipulated time t0 (=2) time (t8), closure signal follower 56 output closure signal.Thus, rotating speed limit switch 52 is closed, engine speed is controlled to sets rotating speed 1600rpm.Thus, when vehicle driving, stopping after the operation to operating stem, need not wait for that stipulated time t0 just can form engine speed to set changes 1600rpm.
Shown in Figure 11 (c), when operation the state that engine speed is controlled to racing speed a=1950rpm, carry out stipulated time t0 (=2) timing (t9) with the operation of 54 pairs of accelerator pedals 15 of timer.After this, when the operation that stops operating stem, operation becomes cut-out with pressure switch 44, closure signal follower 56 is exported closure signal (t10) at once.Rotating speed limit switch 52 is closed, engine speed is controlled to sets rotating speed 1600rpm.Thus, after the end of job, just can engine speed be travelled with suppressing at once.
(2) control switch 70 cut-outs, testing signal Pd<P1
Figure 12 (a) and (b) be represent under these conditions, engine speed, operation with pressure switch 44, travel with the time plot of relation between the setting value (dial rotating speed) of pressure switch 45 and speed setting dial 46.
Shown in Figure 12 (a), be by below the setting rotating speed 1600rpm of speed setting device 47 settings (such as 1000rpm) with the dial speed setting.No matter whether operate accelerator pedal 15, promptly no matter rotating speed limit switch 52 opens or closes, minimum value is selected all selection dial rotating speeds of loop 53.The throw over switch 66 that will dally is transformed into contact b.Control engine speed along with the dial rotating speed thus, can easily carry out travelling at a slow speed of vehicle.
Shown in Figure 12 (b), be maximum value 1950rpm with the dial speed setting.When accelerator pedal 15 operating provision time t0s (=2) when above, are controlled to engine speed the setting rotating speed 1600rpm (t11) of speed setting device 47.After this, when being (t12) when setting (such as 1000rpm) below the rotating speed 1600rpm with the dial speed setting, engine speed is controlled to be this dial rotating speed 1000rpm.After this, if the dial speed setting is become maximum value 1950rpm (t13), then engine speed is controlled to and sets rotating speed 1600rpm.Thus, be suppressed to major general's engine speed in motion and set below the rotating speed 1600rpm, can prevent that driving motors from excessively turning round.
(3) idle running switch 70 cut-outs, operation are cut off with pressure switch 44
Figure 12 (c) represents engine speed under these conditions, the checkout value Pd of pressure transducer 41, the setting value of speed setting dial 46 and the time plot that travels and concern each other with pressure switch 45.
During vehicle driving, motor driven pressure increases, when the checkout value of pressure transducer 41 is specified value P1 when above (t14), function generator 58 output high level signals.AND gate circuit 59 will be set throw over switch 61 and be transformed into contact a according to travelling with the connection signal of pressure switch and the high level signal of function generator 58.Thus, the setting rotating speed 2150rpm with speed setting device 48 is input to maximum value setting loop 62.Set loop 62 by maximum value and select to set rotating speed 2150rpm, engine speed is controlled to be sets rotating speed 2150rpm.Like this, just can carry out high pass filter and travel, even also can there not be not enough smoothly the travelling of output under the occasion that the motor driven torque is big when vehicle startup.
After this, when the checkout value Pd of motor driven torque minimizing, pressure transducer 41 becomes (t15) below 1, function generator 58 output low level signals.Thus, will set throw over switch 61 and be transformed into contact b.The setting rotating speed 900rpm input maximum value of speed setting device 49 is selected loop 62.Select loop 62 to select the setting rotating speed 1600rpm of speed setting device 47 by maximum value, engine speed is controlled to sets rotating speed 1600rpm.The result, when low horsepower travels, engine speed reduces to sets rotating speed 1600rpm (still, the dial rotating speed is 1600rpm when following, reduces to the dial rotating speed).As described in top usefulness Figure 12 (c), can be only according to loading, engine speed being controlled to.
(4) idle running switch 70 connections, testing signal Pd<P1, dial rotational speed N a=1950rpm
Below, illustrate by the connection of idle running switch 70, the occasion of carrying out the idle running control of engine speed with Figure 13.Be with the action difference of above-mentioned (1)~(3): idle running switch 70 is connected, and accelerator pedal 15 and operating stem all are in and do not have serviceability.Here, mainly be that idle running switch 70 is connected and accelerator pedal 15 and operating stem are in the situation that do not have the engine speed under the serviceability, illustrate and the difference of above-mentioned (1)~(3).
Figure 13, the 14th represents under these conditions, and operation is with pressure switch 44, the time plot that travels and concern each other with pressure switch 45 and engine speed.In Figure 13 (a), travel and cut off with pressure switch 45,13 (b) (c) in operation cut off with pressure switch 44.
Shown in Figure 13 (a), when not operating accelerator pedal 15, operating stem operated separately just begin operation.Processing (the step S5 of Fig. 9) throw over switch 66 that will dally by conversion loop 63 is transformed into contact b.Thus, engine speed is controlled to dial rotational speed N a=1950rpm.When the operation that stops operating stem, carry out the processing of step S8~step S11 of Fig. 9 by conversion loop 63.Therefore, through (t21), idle running throw over switch 66 remains conversion on contact b, and engine speed is held in dial rotational speed N a=1950rpm after the operation that stops operating stem, to stipulated time T1 (=3.5).Thus, at short notice, operating stem is carried out under the occasion of repeatable operation, engine speed can be kept carrying out definitely operation.
After the operation that stops operating stem, during transit time T1 (=3.5) (t22), carry out processing with conversion loop 63 from step S11 to step S12, the throw over switch 66 that will dally is transformed into contact c.Setting rotating speed 1050rpm (racing speed) with speed setting device 71 is input to servocontrol portion 67 thus.Engine speed is controlled to idle running at once sets rotating speed 1050rpm.Consequently can expend by fuel saving, and can reduce noise.
Engine speed is being controlled under the state of racing speed 1050rpm, when operating stem is operated (t24), is being transformed into contact b by processing (the step S5 of Fig. 9), the throw over switch 66 that will dally of changing loop 63.Thus, can when operating stem is operated, engine speed be controlled to dial rotational speed N a=1950rpm, can begin operation at once again.
Shown in Figure 13 (b), when operating stem not being operated, accelerator pedal 15 is operated separately and made vehicle driving (t25).Be transformed into contact b by the processing (the step S5 of Fig. 9) of throw over switch 63, the throw over switch 66 that will dally.Thus, engine speed is controlled to dial rotational speed N a=1950rpm.Under this state, when 54 couples of stipulated time t0 of timer (=2) carry out timing (t26), as described above, will set rotating speed 1600rpm and be input to maximum value and select loop 62.Engine speed is controlled to setting rotating speed 1600rpm.After this, from the operation that stops accelerator pedal 15, to through stipulated time T2 (=5), engine speed is held in sets rotating speed 1600rpm.Thus, leave in short time such as inhibit signals under the occasion of accelerator pedal 15, engine speed is certain, can make vehicle startup at once by pedal operation.
After the operation that stops accelerator pedal 15, through stipulated time T2 when (=5) (t27), by the processing (the step S14 of Fig. 9, step S15) in conversion loop 63, will postpone switch 64 and close, and the throw over switch 66 that will dally is transformed into contact a.Thus, begin to postpone the processing of control device 65.As illustrated in fig. 8 engine speed is decelerated to racing speed 1050rpm.Consequently can stop in the driving motors 1 and cavitate, can suitably engine speed be reduced to racing speed 1050rpm.
Engine speed being controlled under the state of racing speed 1050rpm, decelerator pedal 15 is operated (t28).By the processing (the step S3 of Fig. 9~step S5) in conversion loop 63, will postpone switch 64 and open, and the throw over switch 66 that will dally is transformed into contact b.Thus, make to postpone to control to reset, engine speed is controlled to the preceding rotating speed 1600rpm that slows down at once.Consequently can export high pass filter, vehicle is travelled at once from motor.
Shown in Figure 13 (c), in the process of slowing down, accelerator pedal 15 is operated (t29) under the occasion, will postpone to control and reset.Engine speed is controlled to the preceding rotating speed 1600rpm that slows down.
As shown in figure 14, operating stem and decelerator pedal 15 are being carried out under the composition operation occasion, after the operation that stops operating stem, stop the operation of accelerator pedal 15.After the operation that stops operating stem, through stipulated time T2 when (=5) (t31), by the processing (the step S14 of Fig. 9, step S15) in conversion loop 63, will postpone switch 64 and close, the throw over switch 66 that will dally is transformed into contact a.Thus, engine speed is reduced.
On the contrary, after the operation that stops accelerator pedal 15, stop operation to operating stem.In the time of after the operation that stops operating stem, through stipulated time T1 (=3.5) (t32), be transformed into contact c by processing (the step S12 of Fig. 9), the throw over switch 66 that will dally of changing loop 63.Thus, engine speed is controlled to racing speed 1050rpm at once.
As mentioned above, in an embodiment of the invention, when operating stem not being operated,, just make engine speed decelerate to racing speed 1050rpm in case stop operation to accelerator pedal 15.On the other hand, when not operating accelerator pedal 15,, just can at once engine speed be dropped to racing speed 1050rpm in case stop operation to operating stem.Thus, the cavitation erosion when stopping of preventing to travel, and also the fuel can prevent effectively that operation from stopping the time expending and noise.And be after stopping through passing through stipulated time T2 (=5), engine speed being slowed down to the operation of accelerator pedal 15.Thus, when breaking away from accelerator pedal 15, also engine speed can be kept certain, can carry out vehicle startup at once at inhibit signal.And be after stopping to the operation of operating stem through stipulated time T1 (=3.5), engine speed is descended.Thus, under the occasion of repeatedly operating stem being operated, engine speed still can be kept carrying out definitely operation at short notice.In addition, owing to set these stipulated times T1, T2 for different value, for example set T1<T2 for, thereby travelling, can carry out suitable idle running control respectively during operation.
In the above-described embodiment, adopt the operation of engine speed and accelerator pedal 15 irrespectively still to keep certain valve control mode, still, the present invention can be applicable to the accelerator pedal control mode equally.And, be that engine speed when travelling is controlled at and sets below the rotating speed 1600rpm in the above-described embodiment, but also controlled engine speed when making with operation same or be controlled to racing speed Na.In addition, though be oil hydraulic pump is made capacity-variable type and carry out horsepower control in the above-mentioned mode of execution, also can make the fixed capacity formula.
Above-mentioned mode of execution is applicable to the wheel type hydraulic excavator, but also is applicable to other hydraulic traveling vehicles.And, above-mentioned mode of execution be travel, racing speed when the racing speed when stopping and operation all set equal 1050rpm for, also can set different values for.
In the above-described embodiment, be that maximum speed when travelling gets into that 1600rpm, the maximum speed the when rotating speed when high pass filter travels is got into 2150rpm, operation get into 1950rpm, minimum speed is got into 900rpm and described, but the present invention does not limit to and these values.
As mentioned above,, when operating stem is not operated, stop, just prime mover rotating speed being reduced to gradually the racing speed of the usefulness of travelling in case detect the operation of accelerator pedal at the appointed time if adopt the present invention.When accelerator pedal not being operated, stop in case detecting the operation of operating stem mechanism at the appointed time, just can at once prime mover rotating speed be reduced to the racing speed that operation is used.Thus, the cavitation erosion when stopping of just preventing to travel, and can fuel saving when operation stops, reducing noise effectively.